A great booty is always in fashion. From J.Lo to Jen Selter, celebrities have clearly demonstrated its power—and now we asked celeb trainers to demonstrate the moves it takes to get a kick-ass tush. See the go-to booty workout moves of super-fit stars Jessica Alba, Kelly Ripa, and others.

Trainer: Ramona Braganza. Client: Jessica Alba

The Bulgarian Split Squat: "This is one of the most effective moves for shaping your butt and legs," says Braganza. Stand in front of a low box or step (6 to 8 inches high). Take a big step back, placing the ball of your foot on the box. Lower to a lunge, bending your back leg to 90 degrees and keeping your front knee directly over the toe. Push through your front heel to straighten your legs (don't lock your knees) while keeping your feet in position. Repeat 20 reps, then switch legs. Extra credit: Hold a set of 5- to 10-pound dumbbells the entire time.

Trainer: Anna Kaiser. Client: Kelly Ripa

Sliding Lateral Lunge: Stand with feet hip-distance apart and a towel under your right foot. Keeping the weight in your left heel, bend your left leg into a single leg squat and slide the towel out to the right with your foot, keeping your right leg straight. Push your butt way back (while keeping your chest lifted) so that your left knee is above the ankle and not jutting too far forward. Once you are as low as you can go, drag your right foot back in (keeping the leg straight) and return to standing. Repeat 15 reps, then switch legs.

Trainer: Harley Pasternak. Client: Megan Fox

Single-Leg Dead Lift: "This move targets the back of your thighs, starting from the back of your knees and running all the way up to your butt," says Pasternak. Stand on your left leg, knee very slightly bent, holding 8-pound dumbbells, with your right leg straight and extended behind you. Lift your right leg back to a 90-degree angle with the floor, keeping your spine straight and in one long line with your leg the entire time. Return to standing, but avoid touching your right leg down between reps. Complete 20 reps, then switch legs. Aim for three sets on each leg.

Trainer: Lacey Stone. Client: Amanda Seyfried

Squat Kicks:
Stand with your feet hip-distance apart, hands blocking your face. Lift your right knee up and extend the leg in a front kick (don't lock the knee) as you bring both arms behind your body for balance. Control the right leg down to land in a low squat (keeping both knees behind your toes), then immediately stand back up and kick with your left leg. Repeat this sequence (right kick, squat, left kick, squat) for one minute.

Trainer: Gino Caccavale. Client: Carmen Electra

Kettlebell Cross-Back Lunge: Hold a single kettlebell (or dumbbell) in front of your body, feet hip-width apart. Cross and lunge your left leg behind you, about 8 inches behind your right knee. The kettlebell should be directly over your shoelaces, arms extended. Return to standing and immediately cross your right leg back into a lunge behind your left. Continue alternating for 60 seconds, rest for 20 seconds, then attempt another one-minute set.